The invention relates to a method for the preparation of a dye-containing polymer to be used for the spectroscopic analysis of samples. Such dye containing polymers are used, for example, in fiber optical sensors for the determination of the pH value or of the concentration of oxygen or of the concentration of carbon dioxide in the blood of a patient.
A method of that kind is known from U.S. Pat. No. 4,194,877. In the known method an emulsion polymerization of acrylamide, bisacrylamide and a dye is per formed. In this known method, the dye/acryl/polymer composition is produced in the form of small spheres. Unfortunately, the small spheres produced by this method can have very different sizes and can have highly variable dye concentrations. This is particularly disadvantageous in applications (e.g. in pH measurements) where the dye-containing polymer needs to be as homogeneous as possible.